The present invention relates to an improvement made to panels making it possible to display advertising bills or similar articles. Of course, the panel according to the invention is not limited to such a use.
Hitherto, for displaying bills, the said bills have usually been glued to the surface of the panels used. The operation of attaching and removing the said bills is lengthy and difficult to carry out and requires not only the preparation of a glue, but also the cleaning of the surface, the use of special tools, etc.
In sectors other than bill-posting which requires the positioning of a sheet against a vertical panel, it has been proposed to ensure that the said sheet is retained by means of grippers or by means of magnets when the support is metallic. However, such solutions are not possible for displaying large size bills which may be several meters long and high (generally 3 m.times.4 m).
To solve this problem presented by gluing, U.S. Pat. No. 1,748,220 a long time ago proposed using panels having movable bars supporting elements in the form of needles intended for ensuring the retention of adhesive strips, against which the bill to be displayed is itself laid. Although such a solution makes it possible to solve the problem of coating the panel with glue, it nevertheless requires highly complex means in order to put it into practice. Moreover, the bills (or the like) can easily be torn off from the supporting surface.
For displaying small-size elements, such as, for example, announcements or sundry memoranda, U.S. Pat. No. 3,858,727 proposed using perforated panels. The sheet to be displayed is laid against the panel and retention is ensured by means of a pressing element which comprises, on the one hand, branches or studs capable of fitting into the perforations and, on the other hand, a needle which perforates the sheet. Such a solution can be considered an improvement on conventional thumb-tacks which avoids damaging the display surface. Such a "tacking" system, although suitable for small-size sheets, is nevertheless inappropriate for attaching large-size bills.